Dental materials with surface-functionalized fillers

Abstract

The invention relates to a polymerizable composition which is characterized in that it contains at least one filler that is surface-functionalized with groups of formula (I), wherein groups of formula (I) (A) a -Z-Y—R 2 —SiR 1 3−m —(O—) m   (I), are bonded to the filler via at least one oxygen atom that is bound to the silicon atom of the group of formula (I). The invention also relates to a process for the preparation of the composition according to the invention and its use in particular as a dental material.

1 . A polymerizable composition comprising at least one filler that is surface-functionalized with groups of formula (I), wherein groups of formula (I)
   (A) a -Z-Y—R 2 —SiR 1   3−m —(O—) m    (I),   in which   R 1  represents C 1 -C 15  alkyl, C 2 -C 5  alkenyl or phenyl,   R 2  is missing or represents unbranched or branched C 1 -C 6  alkylene,   Y is missing or represents an ether, thioether, amide, ester or urethane group,   Z is missing or represents an at least divalent linear or branched aliphatic radical with 2 to 40 carbon atoms, which can be interrupted by one or more ether, thioether, amide or ester groups and which can contain one or more cycloaliphatic groups with at least 3 carbon atoms and/or one or more aromatic groups with at least 6 carbon atoms, an at least divalent cycloaliphatic radical with at least 3 carbon atoms or an at least divalent aromatic radical with at least 6 carbon atoms,   A represents in each independently —COOH, —P(O)(OH) 2 , —O—P(O)(OH) 2 , —SO 2 OH, —C(O)—O—C(O)—, —CHO, —NH—C(O)—CHO, —C(O)—CHO, —C(O)—CH 2 —C(O)—CH 3 , —N═C═O or —O—C(O)—CH 2 —C(O)—CH 3 ,   a is 1 to 6 and   m is 1 to 3,   wherein R 2  and Z cannot both be missing,   wherein R 2  and Z can in each case be missing only if Y is simultaneously also missing, and   wherein a is 1 if Z is missing,   are bonded to the filler via at least one oxygen atom that is bound to the silicon atom of the group of formula (I).   
   
   
       2 . The polymerizable composition according to  claim 1 , wherein
 R 1  represents C 1 -C 6  alkyl or phenyl,   R 2  represents linear or branched C 1 -C 3  alkylene,   Y is th missing or represents an ether, thioether, ester or urethane group,   Z is missing or represents an at least divalent linear or branched aliphatic radical with 2 to 20 carbon atoms, which can be interrupted by one or more ether, thioether, amide or ester groups and which can contain one or more cycloaliphatic groups with at least 3 carbon atoms and/or one or more aromatic groups with at least 6 carbon atoms, an at least divalent cycloaliphatic radical with at least 3 carbon atoms or an at least divalent aromatic radical with at least 6 carbon atoms,   A represents in each case independently —COOH, —P(O)(OH) 2 , —O—P(O)(OH) 2 , —SO 2 OH, —CHO, —NH—C(O)—CHO or —O—C(O)—CH 2 —C(O)—CH 3 ,   a is 1 to 3 and   m is 1 to 3.   
   
   
       3 . The polymerizable composition according to  claim 1 , wherein the filler is a particulate filler with an average particle size of from 1 nm to 10 μm. 
   
   
       4 . The polymerizable composition according to  claim 1 , wherein the filler is a monodisperse, nanoparticulate filler based on SiO 2 , oxides of the elements Zr, Ti, Al, Y, La, Ce and/or Yb or their mixed oxides with SiO 2 . 
   
   
       5 . The polymerizable composition according to  claim 1 , wherein the filler has an average particle size of 5 to 200 nm. 
   
   
       6 . The polymerizable composition according to  claim 1 , wherein the filler that is surface-functionalized with groups of formula (I) contains at least 0.01 mmol groups of formula (I) per gram of the filler. 
   
   
       7 . The polymerizable composition according to  claim 1 , wherein the filler is additionally surface-modified with at least one further group. 
   
   
       8 . The polymerizable composition according to  claim 1 , wherein the composition contains at least one radically polymerizable monomer. 
   
   
       9 . The polymerizable composition according to  claim 1 , wherein the composition contains an initiator for radical polymerization. 
   
   
       10 . The polymerizable composition according to  claim 1 , wherein the composition contains at least one monomer with 2 or more polymerizable groups and/or at least one monomer with one or more acidic groups. 
   
   
       11 . The polymerizable composition according to  claim 9 , wherein the composition contains an initiator for photopolymerization. 
   
   
       12 . The polymerizable composition according to  claim 1 , further comprising a filler that is not surface-functionalized with groups of formula (I). 
   
   
       13 . The polymerizable composition according to  claim 1 , comprising
 a) 1 to 60 wt.-% filler that is surface-functionalized with groups of formula (I),   b) 1 to 40 wt.-% filler that is not surface-functionalized with groups of formula (I),   c) 0 to 70 wt.-% diluting and/or crosslinking monomer,   d) 0.1 to 5.0 wt.-% initiator for radical polymerization,   e) 0 to 70 wt.-% acidic monomer and/or solvent.   
   
   
       14 . A surface-functionalized filler, comprising groups of formula (I),
   (A) a -Z-Y—R 2 —SiR 1   3−m —(O—) m    (I),   in which   R 1  represents C 1 -C 15  alkyl, C 2 -C 5  alkenyl or phenyl,   R 2  is missing or represents unbranched or branched C 1 -C 6  alkylene,   Y is missing or represents an ether, thioether, amide, ester or urethane group,   Z is missing or represents an at least divalent linear or branched aliphatic radical with 2 to 40 carbon atoms, which can be interrupted by one or more ether, thioether, amide or ester groups and which can contain one or more cycloaliphatic groups with at least 3 carbon atoms and/or one or more aromatic groups with at least 6 carbon atoms, an at least divalent cycloaliphatic radical with at least 3 carbon atoms or an at least divalent aromatic radical with at least 6 carbon atoms,   A represents in each case independently —COOH, —P(O)(OH) 2 , —O—P(O)(OH) 2 , —SO 2 OH, —C(O)—O—C(O)—, —CHO, —NH—C(O)—CHO, —C(O)—CHO, —C(O)—CH 2 —C(O)—CH 3 , —N═C═O or —O—C(O)—CH 2 —C(O)—CH 3 ,   a is 1 to 6 and   m is 1 to 3,   wherein R 2  and Z cannot both be missing,   wherein R 2  and Z can in each case be missing only if Y is simultaneously also missing, and   wherein a is 1 if Z is missing,   are bonded to the filler via at least one oxygen atom that is bound to the silicon atom of the group of formula (I).   
   
   
       15 . A process for the preparation of a composition according to  claim 1 , comprising reacting a filler with at least one silane and mixing the obtained surface-functionalized filler with further constituents of the composition. 
   
   
       16 . The process according to  claim 15 , wherein the silane has the formula (II)
   (A) a -Z-Y—R 2 —SiX n R 1   3−n    (II),   in which   X represents halogen, hydroxy, C 1 -C 5 -alkoxy or C 1 -C 3 -acyloxy and   n is 1 to 3.   
   
   
       17 . The process according to  claim 15 , wherein
 a) the silane is mixed in liquid form with the filler and   b) the filler is dried to separate off condensation products.   
   
   
       18 . The process according to  claim 15 , wherein
 a) the filler is dispersed in a solution of the silane in a solvent and   b) the filler is separated off and optionally washed one or more times with the solvent from step (a) and/or at least one other solvent,   c) the filler is optionally subjected to a heat treatment and optionally washed again,   d) the filler is dried and   e) the filler is optionally ground.   
   
   
       19 . The polymerizable composition, which is obtainable by a process according to  claim 15 . 
   
   
       20 . The surface-functionalized filler, which is obtainable by a process according to  claim 15 . 
   
   
       21 . The polymerizable composition according to  claim 5 , wherein the filler has an average particle size of 10 to 100 nm. 
   
   
       22 . The polymerizable composition according to  claim 21 , wherein the filler has an average particle size of 10 to 50 nm. 
   
   
       23 . The polymerizable composition according to  claim 6 , wherein the filler contains 0.05 to 2 mmol groups of formula (I) per gram of the filler. 
   
   
       24 . The polymerizable composition according to  claim 23 , wherein the filler contains 0.01 to 1 mmol groups of formula (I) per gram of the filler.